It is known to provide an engine such as an internal combustion engine for a vehicle such as a motor vehicle. The modern two and four cycle internal combustion engines are an elegant and increasingly fuel-efficient machine. Because of the wide ranging needs of vehicle owners, engines of widely different torque and power outputs must be produced. But each different engine size (or displacement) is of complicated construction and requires a large investment to design and manufacture.
In simplest terms, these internal combustion engines typically include a plurality of pistons reciprocating within cylindrical bores and connected to a crankshaft with connecting rods. The crankshaft is supported in the engine block by individual bearing caps. During a combustion pressure induced power stroke, each piston applies torque to the crankshaft to provide the motive power of the engine. The torque and power delivered through the crankshaft is a function of the pressure surface area of the pistons and the length of their power strokes.
This assembly of pistons, connecting rods, crankshaft, and bearing caps is housed in an engine block. The engine block defines the cylinders in which the pistons reciprocate and it locates and supports the crankshaft, connecting rods, and bearing caps or bearing support surfaces. It is open at the bottom. The pistons, connecting rods, crankshaft, and bearing caps or bearing support surfaces are assembled from the bottom of the block after inverting it. Finally the bottom of the block is closed with an oil pan. The engine block also contains engine coolant and lubricating oil passages. A cylinder head closes the tops of the cylinders in the block to define therein each respective combustion chamber with the enclosed piston head. The cylinder head also contains one or more air or fuel/air inlet ports and valves, one or more exhaust gas ports and valves, a spark plug and, often, a fuel injector. It also contains coolant and oil passages. Both the engine block and the cylinder head are metal castings of complex design because of integrated features such as coolant and oil passages. Each casting must be designed for the specified displacement of the engine.
As observed, it is very expensive to manufacture such engines with specifically designed and cast engine blocks and cylinder heads. The complex casting requires a high capital investment manufacturing facility for both casting and machining. As a result, making changes to the design of the engine block are, therefore, difficult to implement.
Further, the bearing caps or bearing support surfaces are made separately and machined to close tolerances. The bearing caps or bearing support surfaces are pre-assembled in the crankcase to enable machining such as by flush grinding of the final bearing surfaces, and then disassembled for inserting the crankshaft and for final crankshaft assembly.
Therefore, it is desirable to realize a large savings in the manufacture of automobile engines if the design and manufacture of the engine block could be simplified. It is also desired to provide a modular approach to making the engine structural components that contain the pistons, connecting rods, crankshaft, and bearing caps or bearing support surfaces. It is further desirable to separate the cylinder block portion of engine construction from the crankcase containing and assembling portion of the engine. Therefore, there is a need in the art to provide a simplified modular engine assembly that meets these desires.